Telegraph system



G. c; CUMMINGS. TELEGRAPH svsmw.

APPLICATION FILED DEC. 24, I919.

mum Aug. 22 11922.

- m ver ar: Georg L. Cummings.

C. CUMMINGEl,

weasel.

OF EAST EV] ELECTRIC CUME'AIQ'Y, INGQBPQRATED, NEW YUP-3 N. '35., A CORPORATI OF NEW YORK.

ASSIGIQ'GR TO WESTERN 'rnnnannrn .srsrnin Application filed December 24:, 1919. Serial No. 347,097.

T 0 all whom it may concern:

Be it known that I, G-nonen C. CUMMINGS, a subject of the King of Great Britain, residing at East Orange, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telegraph systems and more particularly to such systems wherein the si nals are composed of positive and negative impulses. its object is the provision in a telegraph system of means whereby a receiving operator may, during the transmission of a message, break the transmitting operator and reverse the direction of sending with great rapidity.

Tn accordance with the object of the invention there is provided means whereby when the current traversing the line is of a zero value, the receiving apparatus at the transmitting station will be disabled.

In attaining the object'of the invention, there is provided a positive and a negative source of potential at each of the stations, one of which is normally connected with the line for energizing a pair of relays serially connected in the line and which control the operation of the telegraphic receiving apparatus. The telegraphic receiving apparatus at the transmitting station is, however, disabled upon the application of a potential of a different polarity to the line than is normally connected therewith for preventing the reception of false signals. transmitting apparatus at one station is operated during the transmission of a message from the second station, and the sources of potential as applied to the line are of the same polarity, the receiving apparatus at the first station will be operated to give a break signal. Otherwise the receiving operator will receive the signals as transmitted at'the transmitting station.

The invention is illustrated in the accom panying drawing in which there is shown a telegraph system provided for simplex operation.

In the drawing thereis shown atelegraph line 4 extending between the stations X and Y. A pair of relays such as 5 and 6 are serially connected with the line at each of the stations and control through their contacts the operation of suitable recorders or sounders connected therewith. The relays ca-lly with the operator at Y.

may be of the ordinary neutral type as shown or be polarized relays equipped with biasing springs to return the armatures to the nonoperated position. The relays are normally energized since at the one station current of a positive polarity is connected with the line, while current of a negative polarity is connected with the line at the other station. These currents, therefore, normally aid each other and retain the relays 5 and 6 energized as long as such a condition exists. The polarity of the current as applied to the line is, however, adapted to be varied by means of the pole changingrelays 9 and 10 located at each of the stations. These relays are controlled by means of telegraph keys 11 and 12 respectively which connect with the winding thereof a source of battery for effecting their energization. The pole changing relays also perform another function, that is the disabling of the receiving sounder preceding the application to the line of a current of a polarity opposite to that which is normally connected to the line.

Let us now assu ne that the operator at X is desirous of communicating telegraphi- The key 11 would thus be depressed for causing the operation of relay 9 associated therewith. Vfhil keys 11 and '12 have been shown as normally open, it is of course obvious that the contacts of the relays 9 and 10 may be arranged in an inverse order to that shown, to permit of a normally closed position of keys 1i and 12. This relay thereby attracts its armature and closes contacts 13 and 14. It is to be noted, though, that contact 13 is closed before 14: as it desired to maintain the sounder 7 disabled for preventing its operation upon the application to the line of the source of current of a negative polarity, and the subsequent deenergization of relay 5. The time intervening between the opening of the front contact of pole changing relay 9 and the closureof contact 13 is not suflicient to cause relay 5 to become deenergized before the latter contact is closed. Thus, although the energizing circuit of relay 5 is opened prior to the closure of contact 13, the sounder 7 will remain, nevertheless, disabled through the front contact of relay 5 until contact 13 is closed. This thereby prevents the reception of false signals which might lead the transmitting tact 14 as currents of the same polarity are now connected with the line and no current vflows, assuming, of course, that the batteries are of the same potential and that there is no appreciable leakage in the line. This relay thereby releases its armature to open the circuit including the sounder 8. When the key 11 is openedapplied tothe linewhich causes current to flow over-"the line through the relays 5 and 6 for effecting their operation- The latter closes the circuit for the sounder 8 while the former, maintains the sounder 7 inoperative. In this way the operator at station X can communicate telegraphically with the 0perator at station Y and the signals as transmitted by the operator at X will be received on the sounder at station Y.

in the transmission of telegraphic signals by the operator at station X, relay 5 does not follow the signals as created at thisstation. This is not done because the reversals of the polarity produced by operating the key 11 results in broken signals being given by relay 5 owing to the capacity of the line and more particularly when the line is one side of a composite telephone line and the relays used are polarized, in which case capacity surges greatly break up the signals sent from key 11 it attempt is made to. record them at station X.

If the operator at Y desires to break the operator at X during the transmission of a message, key 12 would be depressed, causing. the operation of relay 10 and disconnecting the negative source of current and connecting the positive source thereof to the line. It the condition of the linev is such that current is flowing over the line, the connection of the positive source of current with theline will reduce the current to zero as it will be met by a flow of positive cur rent from the station X. The relays 5 and 6 will thus be deenergized and the circuit for thesounder 7 at station will be opened and the signal received thereon. The sounder 8 will be disabled in the same man, ner. as was the sounder 7 upon the closure of contact 13 as was previously described. The operator at X upon receiving such a signal is at once advised that the operator at.Y desires to send. However, should the relay 9 be operated at the instant key 12 was depressed, a current will thus flow over the line as the positive source connected with the line at station Y, and the negative source at station X are thus in series aiding. The sounder at X. is thus disabled through the contact 13 and will therefore not be affected by the closureot the key 12. The signals will, however, be received on the sounder 8. upside down, or in the reverse positive current is again,

order, assuming relays 5 and 6 are of the polarized variety, or in a bro-ken manner it relays 5 and 6 are of the ordinary neutral type as shown. By' these' terms is meant that it a recorder were connected with the line at station Y the signals would appear as a space where a mark should be and vice versa or be jumbled up; more or less The operator at Y is thereby advised of the condition of the transmitting apparatus at station X. Should the operator at X be sending a series of rapid dot signals and the operator at Y close key l2'to stop the o erator at X, then the first time that key 11 was released and contact 13 broken the sounder i wouldbe operated, as relay 5 is already in its released position.

lit is thus evident from the previousdescription 'that an operator who is "in the act or receiving can reverse the direction of sending'with great rapidity. I

This invention hasbeen shown as applied to a grounded line, but it is of course obvious ti at it is also applicable to metallic lines, in which case the same result would so accomplished. it is, therefore, not intended to limit the invention tothe specific disclosure as herein shown and described.

Vv hat is claimed is: 1. In a telegraph system employing'positive and negative impulses, a line conductor connecting two stations, transmitting and receiving apparatus at each of said-stations connectedwith saidline, and'a pole changing relay operated inresponsetothe actuation of the transmitting apparatusfor d-is-' ablingthe receiving apparatus thereat precedingthe application tothe line of an im pulse 01" a different polarity.

2. In atelegraph s'ystememploying positive and negative current impulses, a line conductor connecting two stations, transmitting and receiving apparatus at each of said stations, electromagnetic means continuously and conductively connected with'said line and arranged to normally disablethe receiving apparatus at each of saidstations, and means responsive to the actu'ationwot the transmitting apparatus at one of said'stations for maintaining the receiving appara tus thereat disabled for preventing the false operation of this apparatus.

In a telegraphsystememploying positive and negative current impulses, a line conductor connecting two stations, transmitting and receiving apparatus at each of said stations, a'relay at each of the stations normally energized for disabling the receiving apparatus associated therewith, and means responsive to the actuation of said transmit ting apparatus for deenergizing the relay at each of the stations and for maintaining the receiving apparatus the transmitting station disabled for preventing its false operation. a i 1 4. In a telegraph system employing positive and negative current impulses, a line conductor connecting two stations, transmitting and receiving apparatus at each of said stations, a relay at each of the stations normally energized for disabling the receiving apparatus associated therewith, and a relay responsive to the actuation of said transmitting apparatus for deenergizing the relay at each" of the stations and for maintaining the receiving apparatus at the transmitting station disabled for preventing its false operation.

5. In a telegraph system employing posi tive and negative currents, a line conductor extending between two remote stations, transmitting and receiving apparatus at each of the stations, means at each of the stations for disabling the receiving apparatus upon the operation of its associated transmitting apparatus, and means serially connected in said line conductor and responsive to the simultaneous operation of the transmitting apparatus at the two stations when the polarity of the current impulses applied to said line at both ends thereoi is the same for causing the operation of the previously disabled receiving apparatus.

6. In a telegraph system employing positive and negative currents, a line conductor extending between two remote stations, transmitting and receiving apparatus at each of the stations, means at each of the stations for disabling the receiving apparatus upon the operation of its associated transmitting apparatus, and relay means responsive to the simultaneous operation of the transmitting apparatus at the two stations when the polarity of the current impulses applied to said line at both ends thereof is the same to cause the operation of one of said receiving apparatus in a reverse order.

7. In a telegraph system employing positive and negative current impulses, a line conductor extending between two remote stations, transmitting and receiving appara tus' at each of the stations associated with said line, and means at each of the stations responsive to the simultaneous operation of the transmitting apparatus at the stations,

whereby the line current is reduced to zero for causing the operation of the receiving apparatus at one of said stations, and the disablement oi. the receiving apparatus at the other station.

In witness whereof, I hereunto subscribe my name this 22nd day of December A. D., 1919.

GEORGE O. CUMMINGS. 

